1. Field of the Invention
The present invention is generally concerned with wiring accessories adapted to fit over the previously bared end of the conductive core of an insulated electric conductor in order to facilitate and render more secure the connection to a terminal of any kind, especially when the conductive core comprises multiple strands.
It is more particularly directed to wiring accessories usually referred to as electric terminal connectors comprising a generally tubular metal part adapted to fit over the previously bared end of the conductive core of the insulated electric conductor concerned and an insulative sleeve having a front portion engaged with the metal part and a rear portion larger than the front portion adapted to fit over the corresponding end of the insulation of the electric conductor.
2. Description of the Prior Art
One of the problems to be overcome in the manufacture of electric terminal connectors of this kind concerns the fastening together of the metal part and the insulative sleeve.
At present this is usually done by overmolding.
This is the case, for example, with the electric terminal connector which is the subject matter of French patent No. 1 468 859.
For anchoring it into the insulative sleeve the metal part has at the inner end a frustoconcial enlargement with both sides of which the synthetic material consituting the insulative sleeve is in contact.
Although this arrangement has proved satisfactory and may continue to prove satisfactory it has the following disadvantages.
Firstly, and most importantly, it is difficult to place the metal part in the mold for overmolding the insulative sleeve, which is detrimental to productivity and therefore to manufacturing cost.
This difficulty is accentuated if, in order to obtain a plurality of electric terminal connectors disposed one after the other in a necklace-like strip as described for example in French patent No. 2 468 224, a plurality of metal parts disposed side by side in the same mold are overmolded simultaneously.
This is why in practise such electric terminal connectors are usually manufactured individually.
In an electric terminal connector with the insulative sleeve overmolded in this way onto the metal part, if the molding interface between the insulative sleeve and the metal part is not properly controlled (and this is not necessarily a simple matter), the molding interface can constitute an obstacle to some strands of the conductive core to be inserted into the metal part and so block the strand or strands concerned. This represents an impediment to correct placing of the electric terminal connector currently being fitted, which may lead to its rejection, and (if the electric terminal connector is eventually fitted despite this difficulty) can lead to problems at a later stage, for example if the strands that were blocked project from the electric terminal connector or are broken off and escape from it. This is quite independent of the effect of any such blocking of strands on the electrical quality of the connection that results.
Finally, and in any event, the mechanical characteristics of the electric terminal connector obtained do not depend only on the inherent characteristics of the metal part and the insulative sleeve constituting it, but also on the quality of the overmolding operation, and this is more difficult to control.
It has also been proposed previously to join the insulative sleeve to the metal part of an electric terminal connector by crimping.
This is the case, for example, in published French patent application No. 2 579 836 and U.S. Pat. No. 2,964,171.
After it is inserted into the previously manufactured insulative sleeve the inside end of the metal part is expanded so that its shape matches the corresponding portion of the sleeve.
However, the risks of blocking and the mechanical characteristics disadvantages resulting from the assembly method used, as briefly explained hereinabove for assembly by overmolding, are encountered in much the same way or even in a more serious way with assembly by crimping.
Given the quality of modern adhesives and the possibility of applying accurately measured amounts of such adhesives, the invention proposes to use an assembly method based on adhesive bonding, with arrangements specifically directed to facilitating such adhesive bonding.